Scintillator panel, and radiation detector

ABSTRACT

A scintillator panel includes a substrate made of an organic material, a barrier layer formed on the substrate and including thallium iodide as a main component, and a scintillator layer formed on the barrier layer and including cesium iodide as a main component. According to this scintillator panel, moisture resistance can be improved by providing the barrier layer between the substrate and the scintillator layer.

TECHNICAL FIELD

The present invention relates to a scintillator panel and a radiationdetector.

BACKGROUND ART

Patent Literature 1 to Patent Literature 3 are known as technologies inthis field.

Patent Literature 1 discloses a scintillator panel. The scintillatorpanel has a metal film provided between a resin substrate and afluorescent body layer.

Patent Literature 2 discloses a radiation detection apparatus includinga scintillator panel. The scintillator panel has a scintillator layerhaving cesium iodide as a main component. Thallium is doped into thescintillator layer. The thallium is highly concentrated near aninterface of the scintillator layer with respect to a substrate.According to a concentration distribution of the thallium, an opticaloutput is improved.

Patent Literature 3 discloses a radiation detector including afluorescent body layer. The radiation detector has a scintillator layerhaving cesium iodide as a main component. Thallium is doped into thescintillator layer. The thallium is highly concentrated on a substrateside in the scintillator layer. According to a concentrationdistribution of the thallium, adhesion between a sensor substrate andthe fluorescent body layer is improved.

CITATION LIST Patent Literature

Patent Literature 1: PCT International Publication No. WO2011/065302

Patent Literature 2: Japanese Unexamined Patent Publication No.2008-51793

Patent Literature 3: Japanese Unexamined Patent Publication No.2012-98110

SUMMARY OF INVENTION Technical Problem

Growth substrates for growing a scintillator layer sometimes havemoisture permeability of allowing moisture to permeate thereinto.Moisture which has permeated into a growth substrate arrives at a baseportion of the scintillator layer. It is known that a scintillator layerformed of cesium iodide is deliquescent. Due to moisture suppliedthrough the growth substrate, deliquescence occurs in the base portionof the scintillator layer. As a result, characteristics of ascintillator panel deteriorate. Accordingly, in this field, it isdesired that the moisture resistance of a scintillator panel having ascintillator layer formed of cesium iodide be improved.

For example, a scintillator panel of Patent Literature 1 has a metalfilm provided between a substrate and a fluorescent body layer. Themetal film hinders movement of moisture from the resin substrate to thefluorescent body layer.

An object of the present invention is to provide a scintillator paneland a radiation detector, in which the moisture resistance can beimproved.

Solution to Problem

According to an aspect of the present invention, there is provided ascintillator panel including a substrate made of an organic material, abarrier layer formed on the substrate and including thallium iodide as amain component, and a scintillator layer formed on the barrier layer andconstituted of a plurality of columnar crystals including cesium iodidewith thallium added thereto as a main component.

In the scintillator panel, the barrier layer is provided between thesubstrate and the scintillator layer. The barrier layer includesthallium iodide as a main component. The barrier layer includingthallium iodide as a main component has properties of allowing scarcelyany moisture to permeate thereinto. As a result, moisture which tends tomove from the substrate to the scintillator layer can be blocked by thebarrier layer. Since deliquescence in a base portion of the scintillatorlayer is curbed, deterioration in characteristics of the scintillatorpanel can be curbed. Accordingly, it is possible improve the moistureresistance of the scintillator panel.

In the scintillator panel, the organic material may be polyethyleneterephthalate. According to this constitution, it is possible to easilyprepare a substrate suitable for the scintillator panel.

In the scintillator panel, the organic material may be polyethylenenaphthalate. According to this constitution as well, it is possible toeasily prepare a substrate suitable for the scintillator panel.

According to another aspect of the present invention, there is provideda radiation detector including a scintillator panel having a substratemade of an organic material, a barrier layer formed on the substrate andincluding thallium iodide as a main component, and a scintillator layerformed on the barrier layer and constituted of a plurality of columnarcrystals including cesium iodide with thallium added thereto as a maincomponent; and a sensor substrate including a photo-detection surfaceprovided with a photoelectric conversion element receiving lightgenerated in the scintillator panel. The photo-detection surface of thesensor substrate faces the scintillator layer.

According to still another aspect of the present invention, there isprovided a radiation detector including a substrate made of an organicmaterial, a barrier layer fainted on the substrate and includingthallium iodide as a main component, and a scintillator layer formed onthe barrier layer and constituted of a plurality of columnar crystalsincluding cesium iodide with thallium added thereto as a main component.The substrate has a photo-detection surface provided with aphotoelectric conversion element receiving light generated in thescintillator layer.

In the radiation detector, light is generated due to radiation incidenton the scintillator panel. Light is detected by the photoelectricconversion element provided on the photo-detection surface. Thescintillator panel has the barrier layer including thallium iodide as amain component between the substrate and the scintillator layer.According to the barrier layer, movement of moisture from the substrateto the scintillator layer can be blocked. Accordingly, sincedeliquescence in the base portion of the scintillator layer is curbed,deterioration in characteristics of the scintillator panel can becurbed. As a result, in the radiation detector, deterioration incharacteristics of detecting radiation is curbed. Accordingly, it ispossible for the radiation detector to have improved moistureresistance.

Advantageous Effects of Invention

According to the present invention, there are provided a scintillatorpanel and a radiation detector, in which the moisture resistance can beimproved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view illustrating a scintillator panelaccording to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a radiation detectoraccording to a second embodiment.

A part (a) of FIG. 3 is a cross-sectional view illustrating ascintillator panel according to Modification Example 1, and a part (b)of FIG. 3 is a cross-sectional view illustrating a scintillator panelaccording to Modification Example 2.

A part (a) of FIG. 4 is a cross-sectional view illustrating ascintillator panel according to Modification Example 3, and a part (b)of FIG. 4 is a cross-sectional view illustrating a scintillator panelaccording to Modification Example 4.

A part (a) of FIG. 5 is a cross-sectional view illustrating ascintillator panel according to Modification Example 5, a part (b) ofFIG. 5 is a cross-sectional view illustrating a scintillator panelaccording to Modification Example 6, and a part (c) of FIG. 5 is across-sectional view illustrating a scintillator panel according toModification Example 7.

A part (a) of FIG. 6 is a cross-sectional view illustrating ascintillator panel according to Modification Example 8, and a part (b)of FIG. 6 is a cross-sectional view illustrating a scintillator panelaccording to Modification Example 9.

A part (a) of FIG. 7 is a cross-sectional view illustrating a radiationdetector according to Modification Example 10, and a part (b) of FIG. 7is a cross-sectional view illustrating a radiation detector according toModification Example 11.

A part (a) of FIG. 8 is a cross-sectional view illustrating a radiationdetector according to Modification Example 12, and a part (b) of FIG. 8is a cross-sectional view illustrating a radiation detector according toModification Example 13.

A part (a) of FIG. 9 is a cross-sectional view illustrating a radiationdetector according to Modification Example 14, and a part (b) of FIG. 9is a cross-sectional view illustrating a radiation detector realized byfurther deforming that in Modification example 14.

A part (a) of FIG. 10 is a cross-sectional view illustrating a radiationdetector according to Modification Example 15, a part (b) of FIG. 10 isa cross-sectional view illustrating a radiation detector according toModification Example 16, and a part (c) of FIG. 10 is a cross-sectionalview illustrating a radiation detector according to Modification Example17.

A part (a) of FIG. 11 is a cross-sectional view illustrating a radiationdetector according to Modification Example 18, and a part (b) of FIG. 11is a cross-sectional view illustrating a radiation detector according toModification Example 19.

FIG. 12 is a cross-sectional view illustrating a radiation detectoraccording to Modification Example 20.

FIG. 13 is a graph showing results of an experimental example.

DESCRIPTION OF EMBODIMENTS

Hereinafter, with reference to the accompanying drawings, embodiments ofthe present invention will be described in detail. In description of thedrawings, the same reference signs will be applied to the same elements,and duplicate description will be omitted.

First Embodiment

As illustrated in FIG. 1, a scintillator panel 1 according to a firstembodiment has a substrate 2, a barrier layer 3, a scintillator layer 4,and a protective film 6. The scintillator panel 1 is combined with aphotoelectric conversion element (not illustrated) and is used as aradiation image sensor.

The substrate 2, the barrier layer 3, and the scintillator layer 4 arelaminated in this order in a thickness direction thereof and constitutea laminated body 7. Specifically, the barrier layer 3 is formed on thesubstrate 2. The scintillator layer 4 is formed on the barrier layer 3.The substrate 2 and the scintillator layer 4 do not directly come intocontact with each other. The laminated body 7 has a laminated body frontsurface 7 a, a laminated body rear surface 7 b, and a laminated bodyside surface 7 c. The laminated body 7 is covered with the protectivefilm 6. Specifically, each of the laminated body front surface 7 a, thelaminated body rear surface 7 b, and the laminated body side surface 7 cis covered with the protective film 6. That is, each of the laminatedbody front surface 7 a, the laminated body rear surface 7 b, and thelaminated body side surface 7 c is not directly exposed to theatmosphere.

The substrate 2 constitutes a base body of the scintillator panel 1. Thesubstrate 2 exhibits a rectangular shape, a polygonal shape, or acircular shape in a plan view. The thickness of the substrate 2 iswithin a range of 10 micrometers to 5,000 micrometers. As an example,the thickness of the substrate 2 is 100 micrometers. The substrate 2 hasa substrate front surface 2 a, a substrate rear surface 2 b, and asubstrate side surface 2 c. The substrate rear surface 2 b constitutesthe laminated body rear surface 7 b. The substrate side surface 2 cconstitutes a portion of the laminated body side surface 7 c. Thesubstrate 2 is made of an organic material. Examples of the organicmaterial include polyethylene terephthalate (PET), polyethylenenaphthalate (PEN), and polyimide (PI).

The barrier layer 3 hinders movement of moisture from the substrate 2 tothe scintillator layer 4. The barrier layer 3 is formed on the substratefront surface 2 a. The thickness of the barrier layer 3 is within arange of 0.001 micrometers to 1.0 micrometer. As an example, thethickness of the barrier layer 3 is 0.06 micrometers (600 angstroms).The barrier layer 3 has a barrier layer front surface 3 a, a barrierlayer rear surface 3 b, and a barrier layer side surface 3 c. Thebarrier layer side surface 3 c constitutes a portion of the laminatedbody side surface 7 c. The barrier layer 3 includes thallium iodide(TlI) as a main component. For example, the TlI content of the barrierlayer 3 may be within a range of 90% to 100%. When the TlI content inthe barrier layer 3 is 90% or more, it may be stated that the barrierlayer 3 has TlI as a main component. For example, the barrier layer 3may be Mulled by a two-source vapor deposition method. Specifically, afirst vapor deposition source containing cesium iodide (CsI) and asecond vapor deposition source containing thallium iodide (TlI) areutilized. The barrier layer 3 is formed by performing vapor depositionof TlI on a substrate prior to CsI. As an example, the thickness of thebarrier layer 3 is approximately 600 angstroms. The thickness of thebarrier layer 3 can be measured by causing a scintillator layer and asubstrate to peel off using a strong adhesive tape or the like andanalyzing a substrate interface using an X-ray fluorescence analysis(XRF) apparatus. Examples of X-ray fluorescence analysis apparatuses caninclude ZSX Primus of RIGAKU Corporation.

The scintillator layer 4 receives radiation and generates lightcorresponding to the radiation. The scintillator layer 4 includes cesiumiodide (fluorescent body material) as a main component. Moreover, thescintillator layer 4 includes thallium as a dopant (CsI:Tl). Forexample, the CsI content of the scintillator layer 4 may be within arange of 90% to 100%. When the CsI content of the scintillator layer 4is 90% or more, it may be stated that the scintillator layer 4 has CsIas a main component. The scintillator layer 4 is constituted of aplurality of columnar crystals. Each of the columnar crystals exhibits alight guiding effect. Accordingly, the scintillator layer 4 is suitablefor high-resolution imaging. For example, the scintillator layer 4 maybe formed by a vapor deposition method. The thickness of thescintillator layer 4 is within a range of 10 micrometers to 3,000micrometers. As an example, the thickness of the scintillator layer 4 is600 micrometers. The scintillator layer 4 has a scintillator layer frontsurface 4 a, a scintillator layer rear surface 4 b, and a scintillatorlayer side surface 4 c. The scintillator layer front surface 4 aconstitutes the laminated body front surface 7 a. The scintillator layerside surface 4 c constitutes a portion of the laminated body sidesurface 7 c described above.

The scintillator layer 4 includes a plurality of columnar crystalsextending in the thickness direction of the scintillator layer 4. Baseportions of the plurality of columnar crystals constitute thescintillator layer rear surface 4 b. The base portions come into contactwith the barrier layer front surface 3 a of the barrier layer 3. Tipportions of the plurality of columnar crystals constitute thescintillator layer front surface 4 a. The columnar crystals formed in anouter circumferential portion of the scintillator layer 4 constitute thescintillator layer side surface 4 c. The laminated body side surface 7 cincludes the substrate side surface 2 c, the barrier layer side surface3 c, and the scintillator layer side surface 4 c. The substrate sidesurface 2 c, the barrier layer side surface 3 c, and the scintillatorlayer side surface 4 c are flush with each other. The expression “flushwith each other” denotes that when the substrate side surface 2 c, thebarrier layer side surface 3 c, and the scintillator layer side surface4 c are viewed in a macroscopic manner, each of the surfaces is includedin the same virtual plane. There may be cases where the substrate sidesurface 2 c and the scintillator layer side surface 4 c have minuteuneven structures such as an undercut, a coarse surface, or burrs whenviewed in a microscopic manner. However, when they are defined to be“flush with each other”, the uneven structures are disregarded.

The protective film 6 covers the laminated body 7. As a result, theprotective film 6 protects the laminated body 7 from moisture. Theprotective film 6 covers the substrate rear surface 2 b, the substrateside surface 2 c, the barrier layer side surface 3 c, and thescintillator layer side surface 4 c, and the scintillator layer frontsurface 4 a. The thickness of the protective film 6 may be substantiallythe same at all places where it is formed. In addition, the thickness ofthe protective film 6 may vary at every place. In the protective film 6,for example, a film portion formed on the scintillator layer frontsurface 4 a is thicker than film portions formed on the substrate rearsurface 2 b, the substrate side surface 2 c, the barrier layer sidesurface 3 c, and the scintillator layer side surface 4 c. The protectivefilm 6 may include polyparaxylylene as a main component. The protectivefilm 6 may be formed by a chemical vapor deposition (CVD) method, forexample.

In the scintillator panel 1, the barrier layer 3 is provided between thesubstrate 2 and the scintillator layer 4. The barrier layer 3 includesthallium iodide as a main component. The barrier layer 3 has propertiesof allowing scarcely any moisture to permeate thereinto. Accordingly,moisture which tends to move from the substrate 2 to the scintillatorlayer 4 can be blocked by the barrier layer 3. As a result,deliquescence in the base portion of the scintillator layer 4 is curbed.Accordingly, deterioration in characteristics of the scintillator panel1 can be curbed.

In the scintillator panel 1, the organic material is polyethyleneterephthalate. According to this constitution, the substrate 2 suitablefor the scintillator panel 1 can be easily prepared. A substratesuitable for the scintillator panel 1 is a substrate which can beevaluated as being favorable when evaluated based on heat resistance atthe time of forming a scintillator layer, handleability at the time offorming a scintillator panel, optical characteristics (reflectivity orabsorptivity) with respect to scintillation light, radiationtransmission properties, availability, price, and the like.

In the scintillator panel 1, the organic material is polyethylenenaphthalate, polyimide, or polyetheretherketone. According to thisconstitution as well, the substrate 2 suitable for the scintillatorpanel 1 can be easily prepared.

Second Embodiment

A radiation detector according to a second embodiment will be described.Actually, a region (side) for achieving electrical conduction isprovided on a sensor panel 11. However, it is not illustrated in each ofthe drawings for the sake of convenience.

As illustrated in FIG. 2, a radiation detector 10 has the sensor panel11 (sensor substrate), a barrier layer 3A, a scintillator layer 4A, anda sealing portion 12. Radiation received from a sealing plate 14 isincident on the scintillator layer 4A. The scintillator layer 4Agenerates light corresponding to the radiation. The light passes throughthe barrier layer 3A and is incident on the sensor panel 11. The sensorpanel 11 generates an electrical signal in response to the incidentlight. The electrical signal is output through a predetermined electriccircuit. According to the electrical signal, a radiation image isobtained.

The sensor panel 11 has a panel front surface 11 a, a panel rear surface11 b, and a panel side surface 11 c. The sensor panel 11 is a CCDsensor, a CMOS sensor, or a TFT panel having a photoelectric conversionelement 16. The sensor panel 11 includes a substrate made of an organicmaterial. A plurality of photoelectric conversion elements 16 aredisposed on the panel front surface 11 a in a two-dimensional manner. Aregion on the panel front surface 11 a on which a plurality ofphotoelectric conversion elements 16 are disposed is a photo-detectionregion S1 (photo-detection surface). In addition to the photo-detectionregion S1, the panel front surface 11 a includes a surrounding region S2surrounding the photo-detection region S1.

The barrier layer 3A is formed on the panel front surface 11 a. Thebarrier layer 3A has the barrier layer front surface 3 a, the barrierlayer rear surface 3 b, and the barrier layer side surface 3 c. Morespecifically, the barrier layer 3A is formed on the panel front surface11 a such that the photo-detection region S1 is covered. The barrierlayer front surface 3 a faces the panel front surface 11 a. When thebarrier layer 3A is viewed in a plan view, the barrier layer 3A issmaller than the sensor panel 11. Accordingly, the barrier layer sidesurface 3 c is not flush with the panel side surface 11 c. In thebarrier layer 3A, excluding the foregoing constitution, the constitutionis otherwise similar to that of the barrier layer 3 in the firstembodiment. For example, a material and the like constituting thebarrier layer 3A are the same as those of the barrier layer 3 accordingto the first embodiment.

The scintillator layer 4A is formed on the barrier layer 3A. Morespecifically, the scintillator layer 4A is formed on the barrier layerrear surface 3 b. That is, similar to the barrier layer 3A, thescintillator layer 4A is also formed such that the photo-detectionregion S1 is covered with the barrier layer 3A therebetween. Accordingto this constitution, light from the scintillator layer 4A can bereliably captured by the photoelectric conversion elements 16. Inaddition, the scintillator layer side surface 4 c is not flush with thepanel side surface 11 c.

The scintillator layer 4A exhibits a truncated pyramid shape. Thescintillator layer side surface 4 c is tilted with respect to thethickness direction of the scintillator layer 4A. In other words, thescintillator layer side surface 4 c is a slope (inclination).Specifically, when the scintillator layer 4A is viewed in across-sectional view in a direction orthogonal to the thicknessdirection, a cross section exhibits a trapezoidal shape. One side on thescintillator layer front surface 4 a side is longer than one side on thescintillator layer rear surface 4 b side.

The sealing portion 12 covers a portion of the panel front surface 11 aof the sensor panel 11, the barrier layer 3A, and the scintillator layer4A. The sealing portion 12 is fixed to the surrounding region S2 on thepanel front surface 11 a. The sealing portion 12 air-tightly maintainsan internal space formed by the sealing portion 12 and the sensor panel11. Due to this constitution, the scintillator layer 4A is protectedfrom moisture.

The sealing portion 12 has a sealing frame 13 and the sealing plate 14.The sealing frame 13 has a frame front surface 13 a, a frame rearsurface 13 b, and a frame wall portion 13 c. The frame wall portion 13 cjoins the frame front surface 13 a and the frame rear surface 13 b toeach other. The height of the frame wall portion 13 c (that is, thelength from the frame front surface 13 a to the frame rear surface 13 b)is higher than the height from the panel front surface 11 a to thescintillator layer rear surface 4 b. A gap is formed between thescintillator layer rear surface 4 b and the sealing plate 14. Thesealing frame 13 may be constituted of a resin material, a metalmaterial, or a ceramic material, for example. The sealing frame 13 maybe solid or hollow. The frame front surface 13 a and a plate rearsurface 14 b, and the frame rear surface 13 b and the panel frontsurface 11 a may be joined to each other using an adhesive.

The sealing plate 14 is a plate material having a rectangular shape in aplan view. The sealing plate 14 has a plate front surface 14 a, theplate rear surface 14 b, and a plate side surface 14 c. The plate rearsurface 14 b is fixed to the frame front surface 13 a. The plate sidesurface 14 c may be flush with an outer surface of the frame wallportion 13 c. The sealing plate 14 may be constituted of a glassmaterial, a metal material, a carbon material, or a barrier film, forexample. Examples of a metal material include aluminum. Examples of acarbon material include carbon fiber reinforced plastic (CFRP). Examplesof a barrier film include a laminated body of an organic material layer(PET and/or PEN) and an inorganic material layer (SiN).

In the radiation detector 10, light is generated due to radiationincident on the scintillator layer 4A, and the light is detected by thephotoelectric conversion elements 16 provided in the photo-detectionregion S1. The radiation detector 10 has the barrier layer 3A includingthallium iodide as a main component between the sensor panel 11 and thescintillator layer 4A. The barrier layer 3A blocks movement of moisturefrom the sensor panel 11 to the scintillator layer 4A. Accordingly,deliquescence in the base portion of the scintillator layer 4A iscurbed. As a result, deterioration in characteristics of the radiationdetector 10 can be curbed.

Hereinabove, embodiments of the present invention have been described.However, the present invention is not limited to the foregoingembodiments and can be performed in various forms. Modification examples1 to 14 are modification examples of the first embodiment. In addition,Modification examples 15 to 20 are modification examples of the secondembodiment.

Modification Example 1

A part (a) of FIG. 3 illustrates a scintillator panel 1A according toModification Example 1. The scintillator panel 1A may further haveanother layer, in addition to the substrate 2, the barrier layer 3, andthe scintillator layer 4. The scintillator panel 1A has a functionallayer 8 as another layer thereof. In the functional layer 8, afunctional layer front surface 8 a faces the substrate rear surface 2 b.The functional layer 8 includes an inorganic material as a maincomponent. The functional layer 8 may be a coating layer formed of ametal foil, a metal sheet, or an inorganic material, for example. Alaminated body 7A including the functional layer 8 is covered with theprotective film 6. That is, the protective film 6 covers a functionallayer rear surface 8 b and a functional layer side surface 8 c of thefunctional layer 8, the substrate side surface 2 c, the barrier layerside surface 3 c, the scintillator layer side surface 4 c, and thescintillator layer front surface 4 a. According to the scintillatorpanel 1A, the scintillator layer 4 can be protected from moistureinfiltrating into the substrate 2 by the barrier layer 3 and thefunctional layer 8.

Modification Example 2

A part (b) of FIG. 3 illustrates a scintillator panel 1B according toModification Example 2. The scintillator panel 1B may have a functionallayer 8A having a constitution different from that in Modificationexample 1. The functional layer 8A is also formed on the substrate sidesurface 2 c, in addition to the substrate rear surface 2 b. That is, thefunctional layer 8A has a first part formed on the substrate rearsurface 2 b, and a second part formed on the substrate side surface 2 c.The first part has the functional layer front surface 8 a and thefunctional layer rear surface 8 b. The functional layer front surface 8a faces the substrate rear surface 2 b. That is, the entire frontsurface of the substrate 2 is covered with the barrier layer 3 and thefunctional layer 8A. The functional layer 8A includes an inorganicmaterial as a main component. The functional layer 8A may be a coatinglayer formed of an inorganic material, for example. A laminated body 7Bincluding the functional layer 8A is covered with the protective film 6.That is, the protective film 6 covers the first part of the functionallayer 8A, the second part of the functional layer 8A, the barrier layerside surface 3 c, the scintillator layer side surface 4 c, and thescintillator layer front surface 4 a. According to the scintillatorpanel 1B, the scintillator layer 4 can be protected from moistureinfiltrating into the substrate 2 by the barrier layer 3 and thefunctional layer 8A.

Modification Example 3

A part (a) of FIG. 4 illustrates a scintillator panel 1C according toModification Example 3. The scintillator panel 1C may have a functionallayer 8B which differs from that in Modification example 1. Thefunctional layer 8B is formed on the protective film 6. Specifically,the laminated body 7 including the substrate 2, the barrier layer 3, andthe scintillator layer 4 is covered with the protective film 6 That is,the protective film 6 covers the substrate rear surface 2 b. Thefunctional layer 8B is formed on a part covering the substrate rearsurface 2 b. Accordingly, the scintillator panel 1C has a laminatedstructure in which the functional layer 8B, the protective film 6, thesubstrate 2, the barrier layer 3, and the scintillator layer 4 arelaminated in this order in the thickness direction. The functional layer8B includes an inorganic material as a main component. The functionallayer 8B may be a coating layer formed of a metal foil, a metal sheet,or an inorganic material, for example. According to the scintillatorpanel 1C, the scintillator layer 4 can be protected from moistureinfiltrating into the substrate 2 by the barrier layer 3 and thefunctional layer 8B.

Modification Example 4

A part (b) of FIG. 4 illustrates a scintillator panel 1D according toModification Example 4. The scintillator panel 1D according toModification Example 4 may have a functional layer 8C which differs fromthat in Modification example 1. The functional layer 8C is formed on theprotective film 6. The functional layer 8C covers at least a portion ofthe laminated body 7. Specifically, the laminated body 7 including thesubstrate 2, the barrier layer 3, and the scintillator layer 4 iscovered with the protective film 6. The protective film 6 has a partcovering the substrate rear surface 2 b and a part covering thesubstrate side surface 2 c. The functional layer 8C is formed on each ofa part covering the substrate rear surface 2 b and a part covering thesubstrate side surface 2 c. Accordingly, the scintillator panel 1D has alaminated structure in which the functional layer 8C, the protectivefilm 6, the substrate 2, the barrier layer 3, and the scintillator layer4 are laminated in this order in the thickness direction. Thescintillator panel 1D has a laminated structure in which the functionallayer 8C, the protective film 6, the substrate 2, the barrier layer 3,and the scintillator layer 4 are laminated in this order in a directionintersecting the thickness direction. The functional layer 8C includesan inorganic material as a main component. The functional layer 8C maybe a coating layer formed of a metal foil, a metal sheet, or aninorganic material, for example. According to the scintillator panel 1D,the scintillator layer 4 can be protected from moisture infiltratinginto the substrate 2 by the barrier layer 3 and the functional layer 8C.

The scintillator panel 1 according to the first embodiment can beobtained by forming a panel base body having the barrier layer 3 and thescintillator layer 4 formed therein on one large substrate 2 and bycutting the panel base body. Accordingly, machining marks correspondingto a form of cutting are generated in the panel side surface 11 c of thescintillator panel 1 sometimes. For example, a laser beam may beutilized in cutting of the panel base body.

Modification Example 5

A part (a) of FIG. 5 illustrates a scintillator panel 1E according toModification Example 5. The scintillator panel 1E may have a meltedregion 5 formed on the laminated body side surface 7 c. The meltedregion 5 is a part realized by portions of the substrate 2, the barrierlayer 3, and the scintillator layer 4 which have been melted andresolidified due to a laser beam. That is, the melted region 5 is forlied on the entire surface of each of the substrate side surface 2 c,the barrier layer side surface 3 c, and the scintillator layer sidesurface 4 c. According to the scintillator panel 1E, cutting using alaser beam can be performed.

Such machining marks are formed through steps as described below. First,the laminated body 7 is formed. Next, the laminated body 7 is irradiatedwith a laser beam from the scintillator layer 4 side. A laser beamperforms cutting in the order of the scintillator layer 4, the barrierlayer 3, and the substrate 2. Cleavability of the substrate 2 is lowerthan cleavability of the scintillator layer 4 and the barrier layer 3made of a plurality of columnar crystals. Accordingly, irradiation of alaser beam continues until the laser beam arrives at the substrate rearsurface 2 b. In other words, irradiation of a laser beam continues fromthe scintillator layer front surface 4 a to the substrate rear surface 2b. As a result, the melted region 5 is formed over the entire surface ofthe laminated body side surface 7 c which is a cut surface.

Modification Example 6

A part (b) of FIG. 5 illustrates a scintillator panel 1F according toModification Example 6. The scintillator panel 1F may have a meltedregion 5A formed in a portion of the laminated body side surface 7 c.The melted region 5A is formed on the entire surface of the substrateside surface 2 c, on the entire surface of the barrier layer sidesurface 3 c, and in a portion on the scintillator layer side surface 4c. Specifically, the melted region 5A is formed in a part on thescintillator layer side surface 4 c connected to the barrier layer sidesurface 3 c.

Such machining marks are formed through steps as described below. First,the laminated body 7 is formed. Next, the laminated body 7 is irradiatedwith a laser beam from the substrate 2 side. A laser beam performscutting in the order of the substrate 2, the barrier layer 3, and thescintillator layer 4. The scintillator layer 4 is aggregation ofcolumnar crystals. Accordingly, the scintillator layer 4 has highcleavability. When a groove or a crack is generated in the base portionof the scintillator layer 4, the scintillator layer 4 is cleaved withthe crack as a starting point. Accordingly, there is no need to continueirradiation of a laser beam from the substrate rear surface 2 b to thescintillator layer front surface 4 a. When a laser beam slightly arrivesat the scintillator layer side surface 4 c from the substrate rearsurface 2 b, irradiation is stopped. Then, the scintillator layer 4 iscleaved with a groove or a crack formed in the scintillator layer 4 as astarting point. According to this cutting method, irradiation of a laserbeam with respect to the scintillator layer 4 can be kept at theminimum. Accordingly, compared to the cutting method in Modificationexample 5, damage to the scintillator layer 4 can be reduced.

Modification Example 7

A part (c) of FIG. 5 illustrates a scintillator panel 1G according toModification Example 7. The scintillator panel 1G may have a meltedregion 5B formed in a portion of the laminated body side surface 7 c.The melted region 5B has a melted portion 5 a formed on the substrateside surface 2 c, and a melted portion 5 b formed in a portion on thescintillator layer side surface 4 c. Specifically, the melted portion 5b is formed in a part on the scintillator layer side surface 4 c on thescintillator layer front surface 4 a side. In other words, the meltedregion 5B is not formed in the base portion of the scintillator layer 4.A melted region connected to the melted portion 5 a may be formed on thebarrier layer side surface 3 c.

Such machining marks are formed through steps as described below. First,the laminated body 7 is formed. Next, the laminated body 7 is irradiatedwith a laser beam from the substrate 2 side. Then, when a laser beamarrives at the substrate front surface 2 a, irradiation is stopped.Through this step, the melted portion 5 a on the substrate side surface2 c is formed. Next, irradiation of a laser beam is performed from thescintillator layer 4 side. Then, when the laser beam arrives at apredetermined depth from the scintillator layer front surface 4 a,irradiation is stopped. That is, irradiation of a laser beam is notcontinuously performed from the scintillator layer front surface 4 a tothe scintillator layer rear surface 4 b. In this stage, integrity of thelaminated body 7 is maintained by the base portion of the scintillatorlayer 4 and the barrier layer 3. Next, the scintillator layer 4 iscleaved with a groove and/or a crack provided in the scintillator layer4 as a starting point. According to this cutting method, irradiation ofa laser beam with respect to the scintillator layer 4 can be kept at theminimum. Accordingly, compared to the cutting method in Modificationexample 5, damage to the scintillator layer 4 can be reduced.

Modification Example 8

A part (a) of FIG. 6 illustrates a scintillator panel 1H according toModification Example 8. The scintillator panel 1H has a protective sheet6A, in place of the protective film 6. That is, the scintillator panel1H has the laminated body 7 and the protective sheet 6A. The protectivesheet 6A is constituted by bonding two sheet members 6 a and 6 b to eachother. Specifically, the sheet member 6 a is disposed such that it facesthe scintillator layer front surface 4 a, and the sheet member 6 b isdisposed such that it faces the substrate rear surface 2 b. A gap may beprovided between the sheet member 6 a and the scintillator layer frontsurface 4 a, and between the sheet member 6 b and the substrate rearsurface 2 b. The sheet member 6 a and the scintillator layer frontsurface 4 a may come into contact with each other. The sheet member 6 band the substrate rear surface 2 b may come into contact with eachother. A surrounding portion of the sheet member 6 a overlaps thesurrounding portion of the sheet member 6 b such that they adhere toeach other. According to this constitution, an internal regioncontaining the laminated body 7 can be air-tightly maintained.Accordingly, the scintillator layer 4 can be protected from moisture.

Modification Example 9

A part (b) of FIG. 6 illustrates a scintillator panel 1K according toModification Example 9. The scintillator panel 1K may have a bag-shapedprotective sheet 6B, in place of the protective film 6 That is, thescintillator panel 1K has the laminated body 7 and the protective sheet6B. The protective sheet 6B has an opening. The protective sheet 6Breceives the laminated body 7 through the opening. After the laminatedbody 7 is received, the opening is closed and is fixed using an adhesiveor the like. According to this constitution as well, an internal regioncontaining the laminated body 7 can be air-tightly maintained.Accordingly, the scintillator layer 4 can be protected from moisture.

Modification Example 10

A part (a) of FIG. 7 illustrates a radiation detector 10A according toModification Example 10. The radiation detector 10A has the laminatedbody 7 of the scintillator panel 1 according to the first embodiment,the sensor panel 11, and the sealing portion 12. The sensor panel 11 hasa constitution substantially similar to that of the sensor panel 11 ofthe radiation detector 10 according to the second embodiment.

The sealing portion 12 has a constitution substantially similar to thatof the sealing portion 12 of the radiation detector 10 according to thesecond embodiment. In the radiation detector 10A according toModification Example 10, the height of the frame wall portion 13 c ofthe sealing frame 13 is higher than the height from the panel frontsurface 11 a to the substrate rear surface 2 b. The sealing frame 13 maybe constituted of a resin material, a metal material, or a ceramicmaterial, for example. When the sealing frame 13 is constituted of ametal material or a ceramic material, an adhesion layer (notillustrated) is formed between the frame front surface 13 a and thesealing plate 14. In addition, an adhesion layer (not illustrated) isformed between the frame rear surface 13 b and the panel front surface11 a. The sealing plate 14 may be constituted of a glass material, ametal material, a carbon material, or a barrier film, for example.Examples of a metal material include aluminum. Examples of a carbonmaterial include CFRP. Examples of a barrier film include a laminatedbody of an organic material layer (PET or PEN) and an inorganic materiallayer (SiN). In the radiation detector 10A, the scintillator layer 4 canbe protected from moisture by the sensor panel 11 and the sealingportion 12.

Modification Example 11

A part (b) of FIG. 7 illustrates a radiation detector 10B according toModification Example 11. The radiation detector 10B has a sealingportion 12A which differs from the radiation detector 10A ofModification example 10. The constitutions of the laminated body 7 andthe sensor panel 11 are otherwise similar to those in Modificationexample 10. The sealing portion 12A has the sealing plate 14 and asealing frame 13A. The sealing frame 13A further has an inner sealingframe 17 and an outer sealing frame 18. The sealing frame 13 has a dualstructure. The inner sealing frame 17 may be constituted of a resinmaterial, for example. The outer sealing frame 18 may be constituted ofan inorganic solid material such as a coating layer formed of aninorganic material or a glass rod, for example. In the radiationdetector 10B, the scintillator layer 4 can be preferably protected frommoisture by the sensor panel 11 and the sealing portion 12A.

Modification Example 12

A part (a) of FIG. 8 illustrates a radiation detector 10C according toModification Example 12. The radiation detector 10C according toModification Example 12 has a laminated body 7C having a constitutiondifferent from that of the laminated body 7 of the sensor panel 11according to the first embodiment. The laminated body 7C has a substrate2A, the barrier layer 3A, and the scintillator layer 4A. The single bodyconstitution of the barrier layer 3A according to Modification Example12 is similar to that of the barrier layer 3A according to the secondembodiment. The single body constitution of the scintillator layer 4Aaccording to Modification Example 12 is similar to that of thescintillator layer 4A according to the second embodiment. Accordingly,the scintillator layer side surface 4 c is tilted with respect to thethickness direction.

The laminated body 7C differs from the laminated body 7 according to thefirst embodiment in that the substrate side surface 2 c and the barrierlayer side surface 3 c are not flush with each other and the substrateside surface 2 c and the scintillator layer side surface 4 c are notflush with each other. When the laminated body 7C is viewed in thethickness direction in a plan view, the substrate 2A is larger than thebarrier layer 3A and the scintillator layer 4A. Accordingly, thesubstrate front surface 2 a has an exposed region S3 exposed from thebarrier layer 3A and the scintillator layer 4A.

The laminated body 7C is attached to the sensor panel 11 such that thescintillator layer front surface 4 a faces the panel front surface 11 a.According to this constitution, the exposed region S3 in the substratefront surface 2 a faces the surrounding region S2 of the panel frontsurface 11 a. The substrate front surface 2 a is separated from thepanel front surface 11 a as much as the heights of the scintillatorlayer 4A and the barrier layer 3A. Here, the sealing frame 13 issandwiched between the substrate front surface 2 a and the panel frontsurface 11 a. The sealing frame 13 and the substrate 2A are fixed toeach other through adhesion. Similarly, the sealing frame 13 and thesensor panel 11 are fixed to each other through adhesion. According tothis constitution, the substrate 2A can exhibit a function as a growthsubstrate for the barrier layer 3A and the scintillator layer 4A, and afunction as a sealing plate in the radiation detector 10C. Accordingly,the number of components constituting the radiation detector 10C can bereduced.

Modification Example 13

A part (b) of FIG. 8 illustrates a radiation detector 10D according toModification Example 13. The radiation detector 10D has the sealingframe 13A which differs from the radiation detector 10C of Modificationexample 12. The constitutions of the laminated body 7C and the sensorpanel 11 are similar to those in Modification example 12. The sealingframe 13A has a constitution similar to that of the sealing frame 13Aaccording to Modification Example 11. Accordingly, the sealing frame 13Ahas the inner sealing frame 17 and the outer sealing frame 18. In theradiation detector 10D, the scintillator layer 4A can be protected frommoisture by the substrate 2A, the sensor panel 11, and the sealing frame13A.

Modification Example 14

A part (a) of FIG. 9 illustrates a radiation detector 10E according toModification Example 14. The radiation detector 10E has the laminatedbody 7, a protective film 6C, and the sensor panel 11. The radiationdetector 10E further has a fiber optical plate (which will hereinafterbe referred to as “an FOP 9”). The FOP 9 is disposed between thelaminated body 7 and the sensor panel 11. The laminated body 7 is joinedto the sensor panel 11 with the FOP 9 therebetween. Specifically, theFOP 9 is disposed between the scintillator layer 4 and the sensor panel11. The FOP 9 has an FOP front surface 9 a, an FOP rear surface 9 b, andan FOP side surface 9 c. The FOP rear surface 9 b comes into contactwith the scintillator layer front surface 4 a. The FOP front surface 9 acomes into contact with the panel front surface 11 a. The FOP sidesurface 9 c is flush with the laminated body side surface 7 c. Theprotective film 6C covers the substrate rear surface 2 b, the substrateside surface 2 c, the barrier layer side surface 3 c, the scintillatorlayer side surface 4 c, and the FOP side surface 9 c. Accordingly, theprotective film 6C is not formed between the scintillator layer 4 andthe FOP 9, and between the FOP 9 and the sensor panel 11. In theradiation detector 10E, the scintillator layer 4 is protected frommoisture. In addition, in the radiation detector 10E, the scintillatorlayer 4 can be preferably optically connected to the sensor panel 11using the FOP 9. Then, in the radiation detector 10E, there is noprotective film 6C between the scintillator layer 4 and the FOP 9, andbetween the FOP 9 and the sensor panel 11. As a result, in the radiationdetector 10E, deterioration in resolution can be curbed.

As a radiation detector 10S illustrated in a part (b) of FIG. 9, theprotective film 6C may cover an outer circumferential surface of thelaminated body 7. The protective film 6C may be formed between thelaminated body 7 and the FOP 9.

Modification Example 15

A part (a) of FIG. 10 illustrates a radiation detector 10F according toModification Example 15. The radiation detector 10F has the sealingportion 12A which differs from that in the radiation detector 10according to the second embodiment. The constitutions of the barrierlayer 3A, the scintillator layer 4A, and the sensor panel 11 are similarto those in the radiation detector 10 according to the secondembodiment. The sealing portion 12A has a constitution similar to thatof the sealing portion 12A according to Modification Example 11. Thesealing portion 12A has the sealing plate 14 and the sealing frame 13A.The sealing frame 13A further has the inner sealing frame 17 and theouter sealing frame 18. In the radiation detector 10F, the scintillatorlayer 4A can be preferably protected from moisture.

Modification Example 16

A part (b) of FIG. 10 illustrates a radiation detector 10G according toModification Example 16. The radiation detector 10G differs from theradiation detector 10 according to the second embodiment in having nosealing portion 12 and having a protective film 6D in place of thesealing portion 12. The constitutions of the barrier layer 3A, thescintillator layer 4A, and the sensor panel 11 are similar to those inthe radiation detector 10 according to the second embodiment. Theprotective film 6D covers the panel front surface 11 a, the barrierlayer side surface 3 c, the scintillator layer side surface 4 c, and thescintillator layer rear surface 4 b. In the radiation detector 10G, thescintillator layer 4A can be protected from moisture. The protectivefilm 6D is made of a material similar to that of the protective film 6.

Modification Example 17

A part (c) of FIG. 10 illustrates a radiation detector 10H according toModification Example 17. The radiation detector 10H is realized byadding a sealing frame 13B to the radiation detector 10G according toModification Example 16. Accordingly, the scintillator layer 4A, thebarrier layer 3A, the sensor panel 11, and the protective film 6D aresimilar to those in the radiation detector 10G according to ModificationExample 16. The sealing frame 13B blocks a joining portion between thesensor panel 11 and the protective film 6D. Accordingly, when viewed inthe thickness direction in a plan view, the sealing frame 13B is formedalong an outer edge of the protective film 6D. The sealing frame 13B maybe constituted of a UV curable resin, for example. According to thisconstitution, invasion of moisture through the joining portion betweenthe sensor panel 11 and the protective film 6D is curbed. Accordingly,the moisture resistance of the radiation detector 10H can be furtherenhanced.

Modification Example 18

A part (a) of FIG. 11 illustrates a radiation detector 10K according toModification Example 18. The radiation detector 10K has no sealingportion 12 of the radiation detector 10 according to the secondembodiment.

The radiation detector 10K has a sealing sheet 12B, in place of thesealing portion 12. The constitutions of the barrier layer 3A, thescintillator layer 4A, and the sensor panel 11 are similar to those inthe radiation detector 10 according to the second embodiment. Thesealing sheet 12B exhibits a rectangular shape, a polygonal shape, or acircular shape in a plan view in the thickness direction. The sealingsheet 12B may be constituted of a metal foil, a metal sheet such as analuminum sheet, or a barrier film, for example. The sealing sheet 12Bcovers the scintillator layer 4A and the barrier layer 3A. Specifically,it covers the scintillator layer rear surface 4 b, the scintillatorlayer side surface 4 c, the barrier layer side surface 3 c, and aportion of the panel front surface 11 a. In a plan view, the sealingsheet 12B is larger than the scintillator layer 4A and the barrier layer3A. An outer circumferential edge 12 a of the sealing sheet 12B adheresto the panel front surface 11 a using an adhesive 15. Accordingly, thesealing sheet 12B and the sensor panel 11 form an air-tight regioncontaining the scintillator layer 4A and the barrier layer 3A.Accordingly, in the radiation detector 10K, the scintillator layer 4Acan be protected from moisture. The adhesive 15 may include fillermaterials. The particle sizes of the filler materials are smaller thanthe thickness of the adhesion layer. In the radiation detector 10K, thescintillator layer 4A can be preferably protected from moisture.

Modification Example 19

A part (b) of FIG. 11 illustrates a radiation detector 10L according toModification Example 19. The radiation detector 10L has a sealing frame12C having a constitution different from that of the sealing sheet 12Baccording to Modification Example 18. The sealing frame 12C exhibits abox shape. The sealing frame 12C has an opening on a bottom surface. Thesealing sheet 12B according to Modification Example 18 has flexibility.On the other hand, the sealing frame 12C according to ModificationExample 19 maintains a predetermined shape and is hard. Accordingly, thesealing frame 12C may be constituted of a glass material, a metalmaterial, or a carbon material, for example. The bottom surface of thesealing frame 12C adheres to the panel front surface 11 a using theadhesive 15. According to this constitution, the scintillator layer 4Ais disposed in an air-tight region formed by the sealing frame 12C andthe sensor panel 11. As a result, the scintillator layer 4A can beprotected from moisture. In addition, since the sealing frame 12C ishard, the scintillator layer 4A can be protected mechanically.

Modification Example 20

FIG. 12 illustrates a radiation detector 10M according to ModificationExample 20. The radiation detector 10M has a barrier layer 3B and ascintillator layer 4B which differ from those in the radiation detector10 according to the second embodiment. The barrier layer 3B has thebarrier layer front surface 3 a, the barrier layer rear surface 3 b, andthe barrier layer side surface 3 c. The scintillator layer 4B has thescintillator layer front surface 4 a, the scintillator layer rearsurface 4 b, and the scintillator layer side surface 4 c. The singlebody constitution of the sensor panel 11 is similar to that in theradiation detector 10 according to the second embodiment. Thescintillator layer 4B is formed on one side surface of the sensor panel11 such that it protrudes from the photo-detection region S1.Specifically, first, the barrier layer 3B is formed on thephoto-detection region S1, the panel side surface 11 c on one side, anda peripheral region S2 a between the photo-detection region S1 and thepanel side surface 11 c on one side. Then, the scintillator layer 4B isformed on the entire surface of the barrier layer 3B such that thebarrier layer 3B is covered. The radiation detector 10M having thisconstitution can be preferably used as a radiation detector formammography. In such application of the radiation detector 10M, thescintillator layer 4B is disposed such that a side formed to protrudefrom the photo-detection region S1 is positioned on the breast-wall sideof an examinee.

Experimental Example

In the experimental example, effects of improvement in moistureresistance exhibited by the barrier layer, have been confirmed. Themoisture resistance stated in the present experimental example denotes arelationship between a time being exposed to an environment havingpredetermined humidity and a degree of change in resolution (CTF)indicated by the scintillator panel. That is, high moisture resistancedenotes that the degree of deterioration in resolution indicated by thescintillator panel is low even when it is exposed to a humidityenvironment for a long time. On the contrary, low moisture resistancedenotes that the degree of deterioration in resolution indicated by thescintillator panel is high when it is exposed to a humidity environmentfor a long time.

In the experimental example, first, three test bodies (scintillatorpanels) were prepared. Each of the test bodies had a scintillator layerand a substrate. Each of the scintillator layers included CsI as a maincomponent, and the thickness thereof was 600 micrometers. Then, firstand second test bodies had a barrier layer including TlI as a maincomponent between the substrate and the scintillator layer. On the otherhand, a third test body had no barrier layer. The third test body was acomparative example in which a scintillator layer was formed directly ona substrate. The substrate of the first test body was an organicsubstrate including an organic material as a main component. The firsttest body corresponds to the scintillator panel 1 according to the firstembodiment. The substrate of the second test body was a substrate inwhich a protective film including an organic material as a maincomponent was formed on an aluminum base body. The second test bodycorresponds to a scintillator panel according to a reference example.The substrate of the third test body was the same as the substrate ofthe second test body.

The constitutions of the first to third test bodies are as follows.

First test body: a substrate made of an organic material, a barrierlayer, and a scintillator layer.

Second test body: a substrate having an organic layer, a barrier layer,and a scintillator layer.

Third test body: a substrate having an organic layer, (no barrierlayer), and a scintillator layer.

The resolution of each of the first to third test bodies was obtained.The resolutions were adopted as reference values. Next, the first tothird test bodies were installed in an environment testing machine inwhich the temperature was 40° C. and the humidity was set to 90%. Next,the resolution of each of the test bodies was obtained everypredetermined time elapsed from the installation time. Then, the degreesof the ratios of the resolutions obtained with lapse of everypredetermined time to the resolutions (reference values) werecalculated. That is, relative values with respect to the resolutionsbefore the test bodies were installed in the environment testing machinewere obtained. For example, when the relative value was 100 percent, itindicated that the resolution obtained after the predetermined timeelapsed did not change with respect to the resolution before the testbodies were installed in the environment testing machine and theperformance did not deteriorate. Accordingly, it indicated that as therelative value becomes smaller, characteristics of the scintillatorpanel deteriorate.

A graph shown in FIG. 13 shows a relationship between the time beingexposed to the foregoing environment (horizontal axis) and the relativevalue (vertical axis). The resolution of the first test body wasmeasured after an hour, after 72 hours, and after 405 hours from theinstallation time. Measurement results were indicated as plots P1 a, P1b, and P1 c. The resolution of the second test body was measured afteran hour, after 20.5 hours, after 84 hours, and after 253 hours from theinstallation time. Measurement results were indicated as plots P2 a, P2b, P2 c, and P2 d. The resolution of the third test body was measuredafter an hour, after 24 hours, after 71 hours, and after 311 hours fromthe installation time. Measurement results were indicated as plots P3 a,P3 b, P3 c, and P3 d.

The measurement results thereof were confirmed that performance of thethird test body (plots P3 a, P3 b, P3 c, and P3 d) having no barrierlayer deteriorated the most among the first to third test bodies. It wasassumed that deterioration in performance occurred in the third testbody because moisture percolated from the organic layer to thescintillator layer and deliquescence of the scintillator layerprogressed with lapse of time due to the percolated moisture. On theother hand, regarding the first and second test bodies (plots P1 a, P1b, and P1 c; and plots P2 a, P2 b, P2 c, and P2 d) as well, it could beconfirmed that the relative values tended to drop with the lapse oftime. However, it was obvious that the degrees of drop in relative valueindicated by the first and second test bodies were further curbed thanthe degree of drop in relative value indicated by the third test body.Accordingly, it has been found that deterioration in characteristics ofa scintillator panel can be curbed by providing a barrier layerincluding TlI as a main component. It has been found that a barrierlayer including TlI as a main component can contribute to improvement inmoisture resistance of a scintillator panel.

REFERENCE SIGNS LIST

-   -   1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1K Scintillator panel    -   2, 2A Substrate    -   2 a Substrate front surface    -   2 b Substrate rear surface    -   2 c Substrate side surface    -   3, 3A, 3B Barrier layer    -   3 a Barrier layer front surface    -   3 b Barrier layer rear surface    -   3 c Barrier layer side surface    -   4, 4A, 4B Scintillator layer    -   4 a Scintillator layer front surface    -   4 b Scintillator layer rear surface    -   4 c Scintillator layer side surface    -   5, 5A, 5B Melted region    -   5 a, 5 b Melted portion    -   6, 6C, 6D Protective film    -   6A, 6B Protective sheet    -   6 a, 6 b Sheet member    -   7, 7A, 7B Laminated body    -   7 a Laminated body front surface    -   7 b Laminated body rear surface    -   7 c Laminated body side surface    -   8, 8A, 8B, 8C Functional layer    -   8 a Functional layer front surface    -   8 b Functional layer rear surface    -   8 c Functional layer side surface    -   9 FOP    -   9 a FOP front surface    -   9 b FOP rear surface    -   9 c FOP side surface    -   10, 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10L, 10K, 10M        Radiation detector    -   11 Sensor panel    -   11 a Panel front surface    -   11 b Panel rear surface    -   11 c Panel side surface    -   12, 12A Sealing portion    -   12B Sealing sheet    -   12 a Outer circumferential edge    -   12C Sealing frame    -   13, 13A, 13B Sealing frame    -   13 a Frame front surface    -   13 b Frame rear surface    -   13 c Frame wall portion    -   14 Sealing plate    -   14 a Plate front surface    -   14 b Plate rear surface    -   14 c Plate side surface    -   16 Photoelectric conversion element    -   17 Inner sealing frame    -   18 Outer sealing frame    -   15 Adhesive    -   S1 Photo-detection region    -   S2 Surrounding region    -   S3 Exposed region    -   S2 a Peripheral region

The invention claimed is:
 1. A scintillator panel comprising: asubstrate made of an organic material; a barrier layer formed on thesubstrate and including thallium iodide as a main component; and ascintillator layer formed on the barrier layer and constituted of aplurality of columnar crystals including cesium iodide with thalliumadded thereto as a main component.
 2. The scintillator panel accordingto claim 1, wherein the organic material is polyethylene terephthalate.3. The scintillator panel according to claim 1 wherein the organicmaterial is one selected from polyethylene naphthalate, polyimide, andpolyetheretherketone.
 4. A radiation detector comprising: a scintillatorpanel having a substrate made of an organic material, a barrier layerformed on the substrate and including thallium iodide as a maincomponent, and a scintillator layer formed on the barrier layer andconstituted of a plurality of columnar crystals including cesium iodidewith thallium added thereto as a main component; and a sensor substrateincluding a photo-detection surface provided with a photoelectricconversion element receiving light generated in the scintillator panel,wherein the photo-detection surface of the sensor substrate faces thescintillator layer.
 5. A radiation detector comprising: a substrate madeof an organic material; a barrier layer formed on the substrate andincluding thallium iodide as a main component; and a scintillator layerformed on the barrier layer and constituted of a plurality of columnarcrystals including cesium iodide with thallium added thereto as a maincomponent, wherein the substrate has a photo-detection surface providedwith a photoelectric conversion element receiving light generated in thescintillator layer.